@sdetweil
Ok. Let me know when you are back and can help again.
Thanks a lot.

It’s not the error I saw before.

@sdetweil
I did. But…

I got the feeling i am not far away from the solution. Have still patient to bring me to that point? :)

@sdetweil
Ok. Within the regex101 there is no mistake. But when I change within the config nothing happens again.

@sdetweil
Meanwhile I found the right place. Sorry for this.
In the pic below you can see the entry.

Does help you?

@sdetweil
I did add the debug setting but presumably at the wrong position.
Thought I should add it here:

module: "calendar",
header: "Familienkalender",
position: "top_left",
                   config:{
                          loglevel: ["DEBUG"],
                                        customEvents: [
                                                {
                                                keyword: "Geburtstag",
                                                symbol: "birthday-cake",
                                                transform: {
                                                        search: "^([^\']*) \'(\\d{4})$",
                                                        replace: "$1 ($2)",
                                                        yearmatchgroup: 2
                                                        }
                                                }

@sdetweil
Finally I got some time to test. See the pic below:

I got the message that there is one entry but no title is shown. Did I do something wrong?

@sdetweil
Thanks for helping.

I tried to figure out. Went to the console tab and put the filter on cal.
I get an error your yearmatch is that right? But I don’t know how to deal with it. Can you give me a hint?

Thank you a lot @sdetweil
Now the right symbol is shown on my screen.

Next I tried to use the transform option:

                {
                        module: "calendar",
                        header: "Familienkalender",
                        position: "top_left",
                                config:{
                                        customEvents: [
                                                {
                                                keyword: "Geburtstag",
                                                symbol: "birthday-cake",
                                                transform: {           
                                                        search: "^(.+) (\\d{4}) Geburtstag$",           
                                                        replace: "$1 ($2)",           
                                                        yearmatchgroup: 2
                                                        }
                                                }       
                                                        ],
                                        calendars: [
                                                {
                                                url: "my-url“,
                                                symbolClass: "fas fa-fw fa-"
                                                }
                                                  ]
                                        }
                },

But when I refresh the browser whithin the Kalender „Familienkalender“ is no entry anymore but the word „loading…“ but nothing new is shown after a while.

What could this circumstance cause?